The invention relates to vertical exhaust systems and exhaust water trap assemblies, including for heavy duty vehicles, such as trucks, tractors, off-road equipment, and the like which utilize a vertical exhaust system, for example in which the exhaust conduit extends vertically alongside the cab of the vehicle.
For reduced emissions, catalytic converters and soot filters have been incorporated in the exhaust system of buses, trucks, and so on. If the exhaust outlet is vertical, there is a possibility that water, such as rain, snow, or bus or truck wash, can enter the upper end of the exhaust system and flow downwardly into contact with the catalytic converter or soot filter unit. The water entering the system can be absorbed in the catalyst/filter mounting mat, e.g. vermiculite, that is typically located between the outer surface of the catalytic converter and the outer body of the exhaust conduit. Mounting mat that is exposed to water results in a much lower push-out force, a measure of the ability for the mat to retain the catalyst/filter in place. In another scenario, freezing of water in the catalytic converter can cause structural damage to the monolithic catalyst. As an additional problem, water flowing through the catalytic converter or soot filter may tend to wash particulate material downwardly where such material collects and clogs the lower surface of the catalytic converter/soot filter causing premature failure thereof.
The present invention arose during continuing development efforts directed toward an improved combination exhaust muffler and aftertreatment element and water trap assembly, including ultra-compact structure.